2018 年 24 巻 2 号 p. 209-214
Subcritical water treatment at temperatures of 140–220°C was applied to polyphenols obtained from Japanese persimmon. Properties of the treated polyphenol solution, such as soluble and insoluble solid contents, freezing-point depression, and DPPH radical scavenging activity, were measured. All tested properties were well expressed by the severity factor reflecting the quantity of energy loaded onto the persimmon polyphenols. At a greater severity factor, precipitation occurred and the soluble solid content decreased. However, polyphenol depolymerization occurred simultaneously owing to the formation of acidic compounds, resulting in greater freezing-point depression. The antioxidative activity of the treated solution was also evaluated by measuring the DPPH radical scavenging activity, and was found to increase with an increase in the severity factor.
